This invention relates generally to paired heddles for weaving looms for the production of thickened warp in woven fabrics.
The heddles are paired on the weaving machine to facilitate the weaving of fabric with a heavy warp. Considering a single heddle pair, one of the two heddles is so shaped that its thread eye is positioned in a rear row, and the other heddle of the pair is so shaped that its thread eye is positioned in a forward row. Due to the offset of the thread eyes displaced from the center line of the frame bars on which the heddle pair is mounted upright, such arrangement assures that the passage for the warp even at the broadest part of the heddle, i.e., in the area of the thread eyes, is substantially increased.
Such heddles mounted in pairs are known in the art and are set forth in FIGS. 1, 2 and 9 of the drawings which will be described in more detail hereinafter.
Modern day weaving machines reach very high speeds of rotation resulting in that the loom shafts severely deform in operation because of the high dynamic loadings. This deformation reaches such a level that the play at which the heddles can arrange themselves orderly in a row on the heddle carrier bars of the loom shafts, disappears, and indeed is overcome. When the heddle play is overcome the heddles are stressed in tension along the length thereof. Heddles of modern design which are structured mainly to be symmetrical therefore are deformed into a shape which, at least partially, is inappropriate for the structural loads. Those heddles in the drawings designated 1, 8, 32 and 34 have a high degree of rigidity as compared with heddles 2 and 9. As a result heddles 1, 8, 32 and 34 tend to rapidly deform under tension.
Shown in FIG. 1 is a prior art heddle pair comprising heddles 1 and 2 respectively having centrally located thread eyes 4 and 6 respectively lying along the central axis of that portion of each heddle body which comprises an elongated shaft. The open thread eyes at opposing ends of the shaft provide, as is known in the art, for mounting the heddles in overlying relationship on upper and lower frame bars and/or shafts of the weaving machine (not shown). Thus the thread eyes are offset, to the left and to the right, from the central axis of the frame extending through the upper and lower frame bars.
Heddles 1 and 2 each has a row hole 17 as well as a stamping 18, as known in the art.
Similarly, the prior art heddle pair 8, 9 shown in FIG. 2 is essentially the same as aforedescribed with respect to FIG. 1 except that the end eyes at opposing ends of the shaft of the heddle body of each heddle are C-shaped rather than J-shaped. Thus heddles 8 and 9 respectively contain thread eyes 4 and 5 midway between their ends. In operation, heddle 1 of the heddle pair 1, 2 of FIG. 1 as well as heddle 8 of the heddle pair 8, 9 of FIG. 2, each exhibit a high tensile rigidity in a lengthwise direction, but have a tendency toward rupturing lengthwise, while the other heddles of the pairs, i.e., 2 and 9, respectively, remain undamaged under severe loadings. The reason for this difference in operational behavior could very well be attributed to the fact that the two heddles, 2 and 9, in the area between the end eyes and the thread eyes, i.e., between the end eyes and the heddle shaft, exhibit more resilience as compared to their respective heddles 1 and 8.